| Message ID | 1652175386-31587-1-git-send-email-wanpengli@tencent.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: LAPIC: Disarm LAPIC timer includes pending timer around TSC deadline switch | expand |
On Tue, May 10, 2022, Wanpeng Li wrote: > From: Wanpeng Li <wanpengli@tencent.com> > > The timer is disarmed when switching between TSC deadline and other modes, > however, the pending timer is still in-flight, so let's accurately set > everything to a disarmed state. > > Fixes: 4427593258 (KVM: x86: thoroughly disarm LAPIC timer around TSC deadline switch) > Signed-off-by: Wanpeng Li <wanpengli@tencent.com> > --- > arch/x86/kvm/lapic.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > index 66b0eb0bda94..0274d17d91c2 100644 > --- a/arch/x86/kvm/lapic.c > +++ b/arch/x86/kvm/lapic.c > @@ -1562,6 +1562,7 @@ static void apic_update_lvtt(struct kvm_lapic *apic) > kvm_lapic_set_reg(apic, APIC_TMICT, 0); > apic->lapic_timer.period = 0; > apic->lapic_timer.tscdeadline = 0; > + atomic_set(&apic->lapic_timer.pending, 0); What about doing this in cancel_apic_timer()? That seems to be a more natural place to clear pending. It's somewhat redundant since the other two callers of cancel_apic_timer() start the timer immediately after, i.e. clear pending anyways, but IMO it's odd to leave pending set when canceling the timer. > } > apic->lapic_timer.timer_mode = timer_mode; > limit_periodic_timer_frequency(apic); > -- > 2.25.1 >
On Tue, 10 May 2022 at 21:43, Sean Christopherson <seanjc@google.com> wrote: > > On Tue, May 10, 2022, Wanpeng Li wrote: > > From: Wanpeng Li <wanpengli@tencent.com> > > > > The timer is disarmed when switching between TSC deadline and other modes, > > however, the pending timer is still in-flight, so let's accurately set > > everything to a disarmed state. > > > > Fixes: 4427593258 (KVM: x86: thoroughly disarm LAPIC timer around TSC deadline switch) > > Signed-off-by: Wanpeng Li <wanpengli@tencent.com> > > --- > > arch/x86/kvm/lapic.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > > index 66b0eb0bda94..0274d17d91c2 100644 > > --- a/arch/x86/kvm/lapic.c > > +++ b/arch/x86/kvm/lapic.c > > @@ -1562,6 +1562,7 @@ static void apic_update_lvtt(struct kvm_lapic *apic) > > kvm_lapic_set_reg(apic, APIC_TMICT, 0); > > apic->lapic_timer.period = 0; > > apic->lapic_timer.tscdeadline = 0; > > + atomic_set(&apic->lapic_timer.pending, 0); > > What about doing this in cancel_apic_timer()? That seems to be a more natural > place to clear pending. It's somewhat redundant since the other two callers of > cancel_apic_timer() start the timer immediately after, i.e. clear pending anyways, > but IMO it's odd to leave pending set when canceling the timer. Do it in v2. Wanpeng
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 66b0eb0bda94..0274d17d91c2 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1562,6 +1562,7 @@ static void apic_update_lvtt(struct kvm_lapic *apic) kvm_lapic_set_reg(apic, APIC_TMICT, 0); apic->lapic_timer.period = 0; apic->lapic_timer.tscdeadline = 0; + atomic_set(&apic->lapic_timer.pending, 0); } apic->lapic_timer.timer_mode = timer_mode; limit_periodic_timer_frequency(apic);